Homey Mini for Adafruit Neopixel Ring 16

A big thanks to @bvdp for the very complete build instructions. I've copied and slightly modified the build guide they wrote (below) to align with the changes I made in my build, as well as updated product links.

What you need

• D1 Mini microcontroller (USB-C) (Amazon)
• Adafruit NeoPixel Ring - 16 x WS2812 (Adafruit, AliExpress - Untested)
• Basic soldering gear
• 3D printed case

3D Printing the Case

The case of the Homey mini can be 3D printed in two parts; the Top Case and Bottom Case. These can be printed part-by-part with a manual filament change, or by optionally using an AMS/MMU.

For simplicity, you can print the entire bottom case in a transparent or translucent filament. The original model uses a color change on the bottom case, with the lower portion being black, and the top portion of the bottom case being translucent. You can still use the previous method for better diffusion, but this approach allows for a slightly more accessible build.

The top case can be printed in black.

I’ve used a Bambu Lab P1S printer with AMS system to automatically switch filaments and print both the cases at once by object (see screenshot). I recommend a layer height of 0.12 mm with 15% infill for the top case, and layer heigh of .2 with 100% infill with top surface, bottom surface, and infill set to aligned rectilinear. This allows for a nicer diffusion effect on the bottom case and a great finish on the top case, but these settings are ultimately unimportant.

Installing the software

Homey mini runs on the popular WLED firmware. Installing is as simple as plugging your D1 Mini into your computer using an USB-C cable. Then visit the WLED Web Installer over at https://install.wled.me (make sure to use Chrome or Edge). Follow the instructions to flash the latest WLED firmware. 

When the installation is done, open the WLED interface by visiting the IP address of your D1 Mini in your browser.

Click the Config button, followed by LED Preferences. 

Under Hardware setup set the Length to 16 (the number of LED’s in the NeoPixel Ring). Make sure that the GPIO is set to 2 (this is D4 on the D1 mini). Then click Save. Now that the firmware is installed, you can unplug the D1 mini and continue to the construction part.

Used filaments:

• Top case - Black PLA
• Bottom Case - Clear PETG

Note: You can use whatever clear/translucent filament you have on hand for the bottom case. I used PETG because it's what I had on hand.

Construction

Putting everything together is fairly easy. Solder 3 wires (keep them long enough for now) to the 5V, G and D4 pins of the D1 Mini (this corresponds to pin 2 in wled). Make sure to solder them while the USB-C plug is facing downward. Once the soldering is done, make sure the wires won’t stick out of the back. If they do, cut them down with some flush cutters. 

Align the D1 Mini – with the USB-C connector facing downward – in the cutout on the Bottom Case and press it down firmly. It should fit into the base with a good fit. If you want a more permanent fixture, add a few dabs of superglue to the edge of the board where it contacts the bottom case.

Take the wires coming from the D1 Mini and route them through the center of the NeoPixel Ring, with the LED’s facing down. The ring should snap on the center part of the Bottom Case.

Now shorten the wires (while keeping some slack) and solder them to the pads on the NeoPixel Ring. See the connection diagram above.

Once the soldering is done, it’s time to check if everything works. Connect a powered USB-C cable to the D1 mini and the lights should turn on automatically. 

If everything works correctly you can close the Homey mini by snapping on the Top Case. Just as before, if you want a more permanent fixture, add a few dabs of superglue on the bottom case before putting the top case on. Align the hole for the USB-C connector and press down the Top Case until fully closed.

Usage

Now that your Homey mini is working, you want to connect it to your real Homey for use in Flows.

The most straightforward way is to use the HTTP Request API.
 

Check out the documentation for a complete list of LED controls:
https://kno.wled.ge/interfaces/http-api/
 

Example: 192.168.XX.XX/win&A=255 sets the brightness to maximum

Example: 192.168.XX.XX/win&A=128&FX=0 sets the brightness to half and the effect to Solid

When you create a Flow, select the HTTP Request Logic Card and make a GET request using the URL formatted like the examples above. 

Eventually, I'd like to connect many of these together to make a simple communication device (i.e. update the color on another person's device when you're thinking of them). I'll update the build instructions here when I have time to implement that in a way that's satisfactory.